Multiple site domains and virtual directory single login - asp.net

I am creating a project which has a login portal with multiple applications and websites. I want to allow the user to login and then click any application and have access to it. Some considerations are: each application is defined in a user profile, ie which users can see what. also each application privileges are different for each user. so user a may be an administrator of application a but just a normal users in application b.
What i know.
I can have one auth cookie created in the main portal which with setting the machine key and same authcookie name, each application can use it. I have done a test with this and it seems to work.
My problem
As each site/ virtual directory has different privileges per user and per application when the user access a site i need to get his privileges from the databases but I cant then overwrite the auth cookie userdata with the new details because he may have multiple tabs etc open at a time on different sites. So how can i have an extra cookie store per user and per application for holding application specific details. I know I could go to the database each time but that's allot of overhead for each post back.
Maybe another option is to use the main authcooke for checking the user is logged in then have a new auth cookie per aplication and user, but how can i have 2 authcookies, that may get confusing and the second needs to timeout when the main one does et c i think
Any help suggestions would be gratefully appreciated
THanks
------------------- EDIT -----------------------------
we have one user table for all all sites not 1 per each site. then we map the user to an application and then the user application and role. so when you get to an application it has to check if the user has access and what there role is. all other user details are already in the auth cookie when loggedinto the main site. We do it this way because we have to manage users in one application not each application. Hope this helps understand my requirements.

What you are describing is a 'classic' SSO (single sign-on) example. There are lots of ways people have tried this and they are well documented on Google.
One way to do this is to have your SSO server (e.g. the first place you land and log in) to issue a security 'token' (e.g. a Guid) and then either store this in a cookie or append to URLs. Each subsequent call to an application can look-up the token in a database, verify it's validity and carry on (or boot the user out if invalid).
Using a database also allows you to set a timeout for all applications for which the token is valid.
This can then be extended to allow the database to store which apps each user can access etc. I've described this in very broad terms but it may be a good starting point.
Hope this helps
BTW: querying the database on each request isn't too much of an overhead. I have applications that do just that and are still performant when loaded with 300+ users.

Related

Sharing ASP.NET_SessionId and .ASPXAUTH cookie security risk

We're developing a SAAS solution for a big company in which doctors can view patients and make mutations, order products, provide licenses.
This project is for 4 separate companies under one umbrella company. For each company we developed a portal. All portals use the same code but have a strict separated database because the database contains all the patient information.
We're using Sitecore as CMS.
The client decided to use virtual folders instead of subdomains for the production environment. Our staging evironment url is for example: acc-portal1.umbrella.com. For the production environment they would like a URL such as: acc.umbrella.com/portal1. One SSL certificate is being used for all portals and requests.
We're using Membership Provider (forms authentication) for the authentication of users. Users can not log in with the same account in for example portal1 and portal3 because of the usage of separated databases.
Because we're using formsauthentication the ".ASPXAUTH" cookie is being used. Of course the "ASP.NET_SessionId" cookie is used also.
Because the client wants to use virtual folders instead of subdomains, the cookies are shared over all portals. It is possible to set the "path" on the node in web.config but this path is dynamically read by Sitecore and resolved in a pipeline. I did not find a way to override this path after it is being loaded in the web.config. Also I did not find a way to alter the ASP.NET_SessionId cookie path.
My question is: is it a (security) risk to share these cookies over multiple portals (remember, they should be separated completely)? Are there any other problems this setup could cause?
Hope somebody can help!
Yes, there is a huge security risk. What you do is called a multitenant application. You have to take special steps to ensure that cookies and other sensitive data cannot be shared.
My advice would be to store the tenant name (portal1) in the custom data section of the forms authentication cookie. You set the custom data when you issue the forms cookie.
Then, have a custom module or just a handler of the Application_AuthorizeRequest event, where the identity is already established based on the cookie.
In your handler, you decrypt the forms authentication ticket from the cookie, retrieve the user data and compare to the actual url. If there is a match - nothing happens. If there is no match, it means that user is authenticated in one portal but tries to access another. You can gently clear the response and render a message "well, this portal is not meant for you" or just log the user out.

Creating a Forms Authentication cookie for a search engine crawler

Big picture: I have been asked to create a search engine for our company's intranet. Such a search engine will crawl pages supplied to it by XML files for each independent application on the intranet. Problem is, the entire intranet is using Forms Authentication, and so the crawler will have to have access to each application without actually having user credentials (e.g. username and password).
Each application within the intranet has its access controlled by a permission manager, which is essentially a wrapper on the default Role Manager ASP.NET comes with. Each application can define its own roles and assign people who have those roles.
Please note that there are potentially hundreds of applications.
The crawler has access to the permission manager's database, so it knows what all the roles are. Therefore my idea was to have the crawler create a cookie that identifies it as having all roles for each application.
The problem I'm running into is this: how do I create a forms authentication cookie which already has the roles assigned in it without creating a corresponding user (IPrincipal).
It is entirely possible that I've failed to completely understand how Forms Authentication works, and if so, please tell me what I can do differently.
This is probably not what you want to hear, but...
I would just have the crawler authenticate like anyone else.
Given that this is a crawler you control, why fight Forms Authentication? Seems logical to create a user with all required roles in each application (hopefully you have a central administration point for the hundreds of apps, else I would not want to be an administrator there ;-)
If you do anything that allows "just the crawler" special access (bypass user-based authentication based on... what? The crawler's user agent? A specific origin IP?), you create a security hole that a hacker can leverage to gain access to all of the intranet applications that have otherwise been diligently secured with user IDs, passwords and roles (in fact, the security hole is particularly wide because you propose granting access to EVERY role in the system).
It sounds like what you want is an appropriately encrypted System.Web.Security.FormsAuthenticationTicket (which then gets attached to HTTP requests as a cookie).
The encryption logic is located in System.Web.Security.FormsAuthentication.Encrypt(), which I think uses the MachineKey as the encryption key. Also have a look at the GetAuthCookie() logic (using Reflector).
You might have to write your own version of the encryption method, but what you want to do should be possible, provided you have a copy of the remote site's encryption keys. You don't need the user's passwords -- only the user name is encoded into the Ticket.
It seems to me that the problem is not yet well defined, (at least to me!).
Why do you need to crawl the pages and index them if there are fine grained permissions on them?! How do you show search results without violating the permissions? Why not index the back end by passing the pages altogether (I mean index the database records not the pages)....

SSO - Share single User table between several websites or somehow keep multiple User tables in sync?

I'm working on a single sign-on solution for two ASP.NET MVC3 websites. The sites are on separate subdomains. I'm using Forms Authentication and so far I everything is working well. When I sign into a.example.com I'm automatically signed in to b.example.com too. Nice.
Each application has its own database.
My question is this - if I want to keep certain user information in sync between the two sites (say the last activity date or some user preference) then should I have a User table in both databases and somehow keep them in sync or should only a.example.com's database have a User table and b.example.com somehow reads and writes to it?
Thanks for your advice.
Edit: Thanks to adam I'm leaning towards storing all user data in a separate database. I will pass the authenticated user's username and ID to each application in the authentication cookie. Can anybody offer any advice around maintaining referential integrity between the two databases?
Most SSO solutions I've seen have a central accounts portal where users can maintain settings, change email address etc.
Think Google:
google.com/reader
google.com/analytics
google.com/accounts
This represents a single user store, providing authentication to several sites. This has various benefits, such as a single place to store session hashes and other security details (for preventing things like man-in-the-middle attacks).
In a true SSO, an authentication request redirects to the central auth system (ie google.com/accounts), authenticates and then redirects to the service that requested authentication.
From your description, it sounds like you have separate authentication for each site/service, but the user db is shared.

Approve multiple applications with single sql membership provider

I have an asp.net application that uses the SQL membership provider. I know how to get multiple applications using the same membership provider so a user can go to multiple sites and login using the same credentials. However the requirement on my current project is that each user is given access only to certain applications. For example, the user is given credentials to access Site 1, then at some point in the future, the user needs access to Site 2 and a manager/admin has to allow the user to access Site 2. Or when the manager creates the user's account initially, he/she approves access to the 3 sites (or whatever) the user needs to access.
So my question is what is the best way to use 1 membership provider for many applications, but only allows users to access applications they're approved for (so a manager can manage access to applications, but give users 1 username and password)? I've thought about using roles, but I already use roles in the application for allowing access to certain features in the application. It seems like that would get messy.
I've read about 50 similar questions on SO but none of them addressed the application approval requirement. Thanks in advance.
The easiest straight forward method here is to use roles.
If you add more roles (one for each app) for this purpose it is no big deal. You have a basic role for each app that must be available and check this on Application_AuthenticateRequest or Application_AuthorizeRequest . There are other ways to do it, but this is the least impact, easiest to code (nothing required but a role check), and easy to follow.

Keep User logged in across multiple applications on multiple servers

I am building a suite of applications using ASP.NET.
Each application can be hosted on separate servers.
All the applications share an integrated database.
All applications require user authentication before use.
I want to build the ability to transfer users from one application to another without having to relogin.
Is there a way to recognize that a user is logged in one application and allow quick navigation to another application on a different server?
Currently I am storing the password hashes in the database; but I wouldn't be opposed to other suggestions if they solve the problem.
Here is what I have done in the past.
Each application must share a forms authentication ticket. To do this the forms authentication cookie name must have the same name, the machineKeys must be the same, and the protection mode must be the same.
This works across domains, but does not work across IPs. What I do to get around this is to serialize the ticket info and store it in the database with the session id as the key. If a user is not authenticated the server will look for the session id in the database and rebuild the FA ticket if found.

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